The invention relates in general to electrical in-floor power and communications distribution systems for commercial buildings and the like, and in particular to a metallic floor box with a non-metallic riser that accommodates varying floor material depths and multiple services.
Conventional electrical floor boxes are problematic when used in connection with poured floors, such as concrete floors. One particular type of problem arises because the overall height of the floor box is typically fixed and, thus, if the final height of the poured floor is less than the height of the floor box, the floor box will protrude from the floor. Alternatively, if the planned height of the floor is greater than the overall height of the box, it is necessary to artificially elevate the floor box within the floor when it is installed, for example, using a sub-floor material, and somehow level the sub-floor and/or the box before pouring the floor. Subsequently, if the top of the floor box had not been leveled precisely, the top of the box will not be flush with the top of the poured floor, that is, it would either protrude above the floor or it would be recessed within the floor.
Additionally, various building codes limit the amount and type of electrical wiring and connections that a floor box can contain within a particular volume and other codes require boxes that accommodate multiple services, such as power and data, maintain physical separation between the various services within the box. Therefore, in order to satisfy these requirements, it is necessary to determine the interior volume of the floor-box before the components housed within it can be wired and activated and, further, to maintain separation between various services within the box.
Addressing some of the problems mentioned above, it is known to provide floor-boxes which are set in poured concrete floors and the tops of which are sawed-off to accommodate the depth of the poured floor. One such floor-box is disclosed in U.S. Pat. No. 5,466,886 (the '886 patent), assigned to the same assignee as the present invention, Hubbell Incorporated. In addition to disclosing a variable height floor-box, the '886 Patent further discloses an electrical outlet box assembly for separating and insulating high voltage power wires from low voltage communication wires. The electrical outlet box assembly includes a non-metallic one-piece tubular housing adapted to be embedded into a poured concrete floor having an electrical shielding assembly coupled within the housing.
One disadvantage to the device disclosed in the '886 patent, however, is that it comprises a one-piece non-metallic tubular structure for the housing, which is not ideal for certain applications. For example, certain jurisdictions require the use of metal conduit and outlet boxes. That is, according to code in some jurisdictions, non-metallic boxes may be prohibited and termination of metal conduit into a non-metallic box may be cost prohibitive or disallowed by local authorities. In particular, it is often required to utilize EMT (Electrical Metallic Tubing) conduit to carry the wiring and/or cabling to and from the box. Moreover, due to the shape of the locking nut, even if it were permissible to terminate metallic conduit to a non-metallic box, it would be extremely cumbersome to do so, if it were possible at all.
Accordingly, the device disclosed and claimed in accordance with the present invention addresses the above and other disadvantages encountered with related-art floor-boxes.